Today I was converting an ECO III application originally written in Borland Developer Studio 2006, to an ECO IV application using RAD Studio 2007, when I stumbled across an interesting problem. The application talks to an InterBase database, and was using the Borland Data Provider components for its database connectivity. While BDP is still included in RAD Studio 2007, it has been deprecated and dbExpress is now the preferred data access framework to use. So, as well as converting the app to use...

I often feel a lot of different emotions when using ECO, including happiness, smugness (knowing all the other suckers are coding the hard way) and frustration (usually due to inexperience :-)). But today it invoked another emotion... laughter. I was attempting to use the IOclPsService to execute an OCL statement when I was greeted with the following error Now, I'm not sure what tickled me the most about this error message. The fact that ECO found the error to be strange, or that ECO c...

I recently found myself investigating the answer to the question "When calling TReferenceHandle.SetElement, when does this take effect?". By which I mean, when should I successfully be able to call TReferenceHandle.FieldByName('SomeAttribute').AsString and have this return the value of the attribute for the ECO class instance which was just assigned to the reference handle? The reason this question came up was that I discovered some unexpected behaviour when debugging a problem using a Rave rep...

I encountered a problem yesterday when attempting to perform arithmethic OCL operations on two attributes in my model which had different data types. One attribute is modeled as System.Double (TotalHours) and the other is modeled as System.Decimal (Rate). I needed to work out the total billable amount by multiplying the total hours worked by the rate per hour, and had expected that I could use the expression 'TotalHours * Rate' to create a derived attribute to express this calculation. However, ...

As John Kaster announced yesterday, we now have support for Windows Live Writer on the CodeGear blog server. This post is primarily intended for me to test its support, but I'll also take the opportunity to clarify yesterdays post about formatting numeric attributes in ECO. While the blog post specifically discussed formatting numeric attributes, the technique can also be applied to other data types. For example, the following code would work on a DateTime attribute :-var x: TADONETDateTimeFie...

Let me start off by saying that the contents of this blog post is derived from a technique shown to me today by Jose Maria Sanmartin. Full credit should go to him for providing the meat in this particular sandwich. Normally when data-binding to ECO attributes in VCL.NET there doesn't appear to be any opportunity to format the output. This is less than ideal if you are displaying things such as currency data to the user. In a standard VCL database application, you could use the DisplayFormat a...

If you've ever wondered what ECO is, and what it can do for you, Peter Morris has recently updated the CapableObjects site with an excellent overview. I strongly suggest anyone interested in a significant increase in their development productivity go and take a look. In fact, I'd like to take this opportunity to say 'Well done, Pete!' for all the excellent ECO IV documentation he's been creating. This is an area that has been found wanting in the past, but Pete is doing an excellent job of ad...

Last night while working on an ECO IV VCL.NET application I encountered some behaviour which was initially unexpected, but made perfect sense upon reflection. I have a modal dialog which is used to edit an ECO class instance selected in a TDBGrid. This form had a TReferenceHandle which had its Element property set to the passed in class instance. There were some databound controls bound to this reference handle, as well as some non-bound controls which were used to collect data which was manu...

ECO IV has a handy new feature which allows you to perform a quick prototype on your model. This launches an EcoSpace debugger form which will allow you to see and edit all the classes in an EcoSpace, and also allow you to evaluate Object Constraint Language expressions against it. It also optionally allows you to persist any changes made to an XML file, which can be used again for future prototyping sessions. This feature uses the EcoSpace debugger which was made available in ECO III. It is...

My good friend and ECO guru Holger Flick has written a blog post summarizing a CD database application he wrote in ECO IV with CodeGear RAD Studio. In it he also claims "...I am a slow typer as I hardly ever have to type". His rationale being that since discovering ECO he doesn't have to type anywhere near as much, so his typing skills are on a steady decline. :-)...